SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003a139596171fbd8a25893fde253cfc1fb3918864e92955a30f261310802368' 
  AND token = 'G4d+JDIulVFlVAMr6giWTpliEvBiJyzQmi/70foOxMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}